26 May 2012

Life skills - resizing, alignment, levels in photos

It's all too common to have a photo - or part of a photo - that's not quite straight. And it's all too common to have stuff round the edges of the photo that you want to get rid of, as in my photo of a page of a book.

First I used the Crop tool (4th from the top in the tool bar on the left of the screen - it looks like a hache or a box) to select the area I wanted to keep. I made it slightly bigger than needed, to allow for the straightening up adjustment -

Double click on the image and the unwanted bit falls away.

Now, a sequence of two very useful keystrokes - they're in the menu bar somewhere, but it's SO much quicker to remember a few keystrokes than to be forever mousing around. Control + A to "Select All" - that gives you the dotted line around the image - and Ctl + T to "Transform" - that lets you change the shape of the image; it puts "handles" into the dotted line. These look like boxes at the corners and middle -

Holding down the Control key, grab the corners and move them, one after another, until the image is straight. This is the fun part. If you don't like the result, return the handles to where they were and try again. To check that it's aligned, you can use the handles in the middle, stretching them outward till the lines in your image meet the edge, then returning them and doing any further adjustment. (Sorry there's no photo for this; I only thought of it just now while writing.) Remember to use the Control key while doing this.

Once it's aligned, double click in the image. Before you can crop it (see above), you need to click outside the image to make the dotted line disappear.

Once you've cropped the image, you might want to adjust for brightness and contrast. You can do this from the menu bar (under Image - Adjustments - Brightness and contrast) - or with a keystroke shortcut, you can bring up the Levels box and have fun with the sliders. The keystroke is Ctl + L.

These screenshots are quite small (clicking on them doubles their size) but if you look carefully at the two Levels screens you can see a difference. The sliders - the arrows under the histogram (the "mountain") - have moved. Instead of being at the ends and middle of the box, they are now at the ends of the histogram - and I moved the one in the middle till the contrast in the image looked optimal. You see the levels changing as you move the sliders.

Before and after - what a difference!

With the keystroke shortcuts - and a bit of practice - this entire procedure takes less than a minute.

Tuesday is Drawing Day - why not join in, wherever you are? Find somewhere that has interesting things - it needn't be a museum, it could be your own home! - and just draw, using whatever media you want. Ask some friends to join you, then have a nice lunch.

The London group has grown to the point where it's getting difficult to find a cafe table large enough, and reluctantly I must say that it is no longer open to new members.

8 August - Docklands, either the architecture or the covered garden or the museum. Meet in the museum cafe for lunch.